If you are using WPML, the Redirection plugin may create a redirect loop once you update any page, regardless of that page being redirected to or from. I had to delete all redirections (after hours of work creating them) and the Redirection plugin in order to resolve the redirect loop for these pages. The Redirect plugin created a non-existent language translation, adding /it/ to the URL as if there was Italian in my multilingual site. For some reason any updated page became a rediret loop. wrd_redirection_items table shows the /it/ thing: